In the prior art, when a user equipment (UE) is transferred from a packet switched (PS) domain to a circuit switched (CS) domain, if the UE is involved in multiple voice sessions, the UE may determine a target voice session among the multiple voice sessions, and initiate a transfer request of the target voice session to a service centralization and Continuity application server (SCC AS) of a network side. After the target voice session is transferred to the CS domain, a mobile switching center server (MSC Server) takes the place of the UE to initiate transfer of other voice sessions to the SCC AS, and transfer the other voice sessions to the CS domain, and thereby the transfer of all of the sessions of the UE is completed. If the UE is only involved in a video session (a session including a voice media stream and a video media stream at the same time), the UE initiates transfer of the video session to the SCC AS so as to transfer the video session to the CS domain.
The prior art does not provide a method for transferring sessions of a UE when the UE is involved in a video session and a voice session at the same time, so that when a UE is involved in a voice session and a video session at the same time, the sessions of the UE cannot be transferred.